{"Implementation approach": "We will use the Pygame library to create the game interface and handle user input. The game logic will be implemented using Python classes and data structures.", "File list": ["main.py", "game.py"], "Data structures and interfaces": "classDiagram\n    class Game {\n        -grid: List[List[int]]\n        -score: int\n        -game_over: bool\n        +__init__()\n        +reset_game()\n        +move(direction: str)\n        +is_game_over() bool\n        +get_empty_cells() List[Tuple[int, int]]\n        +add_new_tile()\n        +get_score() int\n    }\n    class UI {\n        -game: Game\n        +__init__(game: Game)\n        +draw_grid()\n        +draw_score()\n        +draw_game_over()\n        +handle_input()\n    }\n    Game --> UI", "Program call flow": "sequenceDiagram\n    participant M as Main\n    participant G as Game\n    participant U as UI\n    M->>G: reset_game()\n    M->>U: draw_grid()\n    M->>U: draw_score()\n    M->>U: handle_input()\n    U->>G: move(direction)\n    G->>G: add_new_tile()\n    G->>U: draw_grid()\n    G->>U: draw_score()\n    G->>U: draw_game_over()\n    G->>G: is_game_over()\n    G->>G: get_empty_cells()\n    G->>G: get_score()", "Anything UNCLEAR": "..."}